This paper presents "The Key Sectors" of the Indonesian economy which ware identified by utilising several identification techniques and concepts. The 19 x 19 sector classification of the Indonesian 1975 Input - Output Table has been used as the basis of study. The results not only provide a useful quantitative indication of the sectoral importance in the Indonesian economy but they also reveal the main areas on which, for the purposes of allocation of scarce resources, either the government or private investors should concentrate.